REPORT ON THE AMPHIPODA. 1141 



to the Challenger species. The finger, however, in each gnathopod, is figured without the 

 least trace of dentation on the inner margin, and the tuberculatum of the palm in the 

 second gnathopod, though similar, is not exactly like that of our species. Considering 

 the enormous distance between the places of capture, I have not thought it right to 

 identify the two forms. Had they belonged to a single species of so wide a distribution, 

 it is highly improbable that it would have escaped discovery for so long, and then 

 suddenly have been discovered almost simultaneously at two enormously distant points. 



Podocerus tristanensis, n. sp. (PI. CXXL). 



Rostrum minute, lateral lobes of the head not large or very prominent, acute above. 



Eyes rounded, oval, occupying the lateral lobes of the head, dark in the specimens 

 preserved in spirits. 



Upper Antennae. — The first joint thick, not quite so long as the head ; with setiform 

 spines at four or five points of the lower margin ; the second joint longer, much thinner, 

 with spines at five points of the lower margin ; the third joint about as long as the 

 second, with spines at six points, several of them feathered and of great length, on 

 each joint the distal spines the longest ; the flagellum of four joints, together longer 

 than the third joint of the peduncle, with similar spines at each lower apex, the first 

 joint the longest of the four and having spines at two points of the lower margin besides 

 those at the apex. 



Lower Antennas. — The first two joints short, gland-cone small, decurrent ; the third 

 longer than the preceding two united; the fourth as long as the second of the upper 

 antennae and stouter, with spines at five points of the lower margin; the fifth joint rather 

 longer, with six groups of spines ; the flagellum of four joints, together as long as the third 

 and fourth of the peduncle united, all carrying long apical spines and setae, but not so long 

 as those on the upper antennae; the spine at the apex of the fourth joint shorter than 

 the others. 



Mandibles. — The cutting edge of both the principal and secondary plates appeared 

 to be cut into several little teeth, of which two only on the right mandible are conspicuous 

 in the secondary plate ; the spine-row consisting of three denticulate spines on the left, 

 and two on the right, mandible ; the molar tubercle prominent, with strongly denticulate 

 crown and a long seta ; the laminar process on the front margin of the tubercle seems 

 to be similar to that described for Podocerus falcatus; the first joint of the palp short, 

 widening a little distally, the second joint longer than the third, with about seven pairs 

 of spines along the front ; the third joint with about a dozen long pectinate spines round 

 the broad apex, three or four on the convex front margin, a row of four long ones across 

 the middle of the outer surface, and two, one above the other, close to the convex outer 

 margin. 



